Four members of a group of 31 North Koreans who accidentally crossed over into South Korean waters on a fishing boat, have decided to defect to the South, despite Pyongyang's demands that they all be repatriated to the North. The South Korean Red Cross said, the remaining 27 members of the group will be sent back through Panmunjom, a truce village on the ground border between the two sides. The defection of the four North Koreans could spark tensions on the peninsula, where joint U.S.-South Korea military drills have kicked off this week. North Korea had threatened to use weapons of mass destruction.